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62579266 RV |
1 | /* |
2 | * Copyright (C) ST-Ericsson SA 2010 | |
3 | * | |
4 | * License Terms: GNU General Public License v2 | |
5 | * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> | |
6 | */ | |
7 | ||
8 | #include <linux/kernel.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/platform_device.h> | |
13 | #include <linux/spi/spi.h> | |
14 | #include <linux/mfd/ab8500.h> | |
15 | ||
16 | /* | |
17 | * This funtion writes to any AB8500 registers using | |
18 | * SPI protocol & before it writes it packs the data | |
19 | * in the below 24 bit frame format | |
20 | * | |
21 | * *|------------------------------------| | |
22 | * *| 23|22...18|17.......10|9|8|7......0| | |
23 | * *| r/w bank adr data | | |
24 | * * ------------------------------------ | |
25 | * | |
26 | * This function shouldn't be called from interrupt | |
27 | * context | |
28 | */ | |
29 | static int ab8500_spi_write(struct ab8500 *ab8500, u16 addr, u8 data) | |
30 | { | |
31 | struct spi_device *spi = container_of(ab8500->dev, struct spi_device, | |
32 | dev); | |
33 | unsigned long spi_data = addr << 10 | data; | |
34 | struct spi_transfer xfer; | |
35 | struct spi_message msg; | |
36 | ||
37 | ab8500->tx_buf[0] = spi_data; | |
38 | ab8500->rx_buf[0] = 0; | |
39 | ||
40 | xfer.tx_buf = ab8500->tx_buf; | |
41 | xfer.rx_buf = NULL; | |
42 | xfer.len = sizeof(unsigned long); | |
43 | ||
44 | spi_message_init(&msg); | |
45 | spi_message_add_tail(&xfer, &msg); | |
46 | ||
47 | return spi_sync(spi, &msg); | |
48 | } | |
49 | ||
50 | static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr) | |
51 | { | |
52 | struct spi_device *spi = container_of(ab8500->dev, struct spi_device, | |
53 | dev); | |
54 | unsigned long spi_data = 1 << 23 | addr << 10; | |
55 | struct spi_transfer xfer; | |
56 | struct spi_message msg; | |
57 | int ret; | |
58 | ||
59 | ab8500->tx_buf[0] = spi_data; | |
60 | ab8500->rx_buf[0] = 0; | |
61 | ||
62 | xfer.tx_buf = ab8500->tx_buf; | |
63 | xfer.rx_buf = ab8500->rx_buf; | |
64 | xfer.len = sizeof(unsigned long); | |
65 | ||
66 | spi_message_init(&msg); | |
67 | spi_message_add_tail(&xfer, &msg); | |
68 | ||
69 | ret = spi_sync(spi, &msg); | |
70 | if (!ret) | |
c0d4010e LW |
71 | /* |
72 | * Only the 8 lowermost bytes are | |
73 | * defined with value, the rest may | |
74 | * vary depending on chip/board noise. | |
75 | */ | |
76 | ret = ab8500->rx_buf[0] & 0xFFU; | |
62579266 RV |
77 | |
78 | return ret; | |
79 | } | |
80 | ||
81 | static int __devinit ab8500_spi_probe(struct spi_device *spi) | |
82 | { | |
83 | struct ab8500 *ab8500; | |
84 | int ret; | |
85 | ||
bde435a9 KW |
86 | spi->bits_per_word = 24; |
87 | ret = spi_setup(spi); | |
88 | if (ret < 0) | |
89 | return ret; | |
90 | ||
62579266 RV |
91 | ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL); |
92 | if (!ab8500) | |
93 | return -ENOMEM; | |
94 | ||
95 | ab8500->dev = &spi->dev; | |
96 | ab8500->irq = spi->irq; | |
97 | ||
98 | ab8500->read = ab8500_spi_read; | |
99 | ab8500->write = ab8500_spi_write; | |
100 | ||
101 | spi_set_drvdata(spi, ab8500); | |
102 | ||
103 | ret = ab8500_init(ab8500); | |
104 | if (ret) | |
105 | kfree(ab8500); | |
106 | ||
107 | return ret; | |
108 | } | |
109 | ||
110 | static int __devexit ab8500_spi_remove(struct spi_device *spi) | |
111 | { | |
112 | struct ab8500 *ab8500 = spi_get_drvdata(spi); | |
113 | ||
114 | ab8500_exit(ab8500); | |
115 | kfree(ab8500); | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | static struct spi_driver ab8500_spi_driver = { | |
121 | .driver = { | |
122 | .name = "ab8500", | |
123 | .owner = THIS_MODULE, | |
124 | }, | |
125 | .probe = ab8500_spi_probe, | |
126 | .remove = __devexit_p(ab8500_spi_remove) | |
127 | }; | |
128 | ||
129 | static int __init ab8500_spi_init(void) | |
130 | { | |
131 | return spi_register_driver(&ab8500_spi_driver); | |
132 | } | |
133 | subsys_initcall(ab8500_spi_init); | |
134 | ||
135 | static void __exit ab8500_spi_exit(void) | |
136 | { | |
137 | spi_unregister_driver(&ab8500_spi_driver); | |
138 | } | |
139 | module_exit(ab8500_spi_exit); | |
140 | ||
141 | MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com"); | |
142 | MODULE_DESCRIPTION("AB8500 SPI"); | |
143 | MODULE_LICENSE("GPL v2"); |